Electroresponsive device



1, 1933. GRUNHQLZ I 1,920,745

ELECTRORESPONS IVE DEVICE Filed Oct. 5, 1927- Inventor-z Hans Gr'u'nholz,

I-ILS Attorney.

Patented Aug. 1, 1933 ELECTRORESPONSIVE DEVICE Hans Griinholz, Charlottenburg, Germany, assignor to General Electric Company, a Corporation of New York Application October 5, 1927, Serial No. 224,269,

and in Germany March 14, 192 7 The invention relates to electroresponsive devices and more particularly to electroresponsive circuit controlling devices of the type having a movable circuit controlling member magnetically 5 held in one position by means of an electromagnet and provided with a releasing winding arranged to magnetically cooperate with the holding electromagnet to release the circuit controlling member upon a predetermined current flow through the releasing winding.

A circuit controlling device of the above character is described and broadly claimed in the Tritle Reissue Patent No. 15,441 of August 2, 1922, which is assigned to the assignee of my present invention. In the circuit interrupter described in the Tritle patent, the releasing winding is arranged to divert or shift the flux of the holding electromagnet from one path to another path in order quickly to release the magnetically held circuit controlling switch member for operation to the circuit opening position. The Tritle type of quick-acting circuit interrupter normally operates in response to an excessive current flow in one direction through the releasing winding. In certain service, however, the releasing winding of the circuit interrupter is subjected to current flow in the opposite direction. For example, where the interrupter is employed to give reverse current protection, the interrupter is arranged to be unresponsive to current flow in the normal direction and respond only to a predetermined current flow in the reverse direction. However, there may result under some circumstances an unde-' sired response of the circuit interrupter in case the current flow in the normal direction is suddenly stopped as by operation of an auxiliary circuit interrupter or switch.

' The principal object of the .present invention is to prevent such undesirable operation of a quick-acting electroresponsive device of the above character.

The undesirable operation of the Tritle type of circuit interrupter when arranged to give reverse current protection under the conditions outlined 0 above is due primarily to the" fact that the flux set up by the releasingwinding opposes the flux set up by the main magnetizing winding of the electroresponsive device upon current flow through the releasing winding in the normal direction, and inherently functions to decrease the effective flux set up by the winding of the holding electromagnet. The releasing winding, upon current flow in the normal direction, supplies flux tending to hold the movable magnetic member of the electromagnet in the attracted po- 11 Claims. (Cl. 175-294) sition. However,'upon a sudden interruption of the current inthe normal direction, the decreased flux of the holding electromagnet may not return to the normal value quickly enough to prevent the magnetic member moving from the attracted position, particularly where the magnetic .member is under a strong bias for movement from the attracted position. The undesired release of the magnetic member is effectively prevented in accordance with the present invention by providing an auxiliary or compensating winding which is energized in accordancewith the current flow in the releasing winding, and is associated with the holding electromagnet in such a way as to strengthen the holding flux of the holding electromagnet when current flows in the releasing winding in the normal direction. In this way it is possible to maintain the flux of the holding electromagnet at substantially normal value in spite of the opposing magnetizing force of the releasing winding during current flow in the normal direction. Thus, in case the current flow in the normal direction should be suddenly interrupted, the normal value of holding flux is available for maintaining the movable magnetic memher in the attracted position.

For a more complete understanding of the present invention, reference is had to the accompanying drawing in which the single figure illustrates a circuit interrupter embodying a preferred form of the invention arranged to provide reverse current protection.

In the drawing the reverse current circuit interrupter is shown diagrammatically and comprises an electromagnet 10 for holding the movable magnetic member 11 in the attracted position to maintain the movable switch element 12 in engagement with the cooperating stationar-y switch element 13. As shown, the movable switch element 12 is carried directly by the movable magnetic member 11 which is mounted upon thepivot pin 14 and biased by gravity or other suitable means to operate the movable switch element 12 to the circuit opening position.

The holding electromagnet 10 is provided with a main magnetizing winding 15 which is normally energized from a suitable source such as the battery B indicated in the drawing. The magnetizing winding 15 supplies flux in the direction of the arrow associated therewith of a normal value sufficient to maintain the movable magnetic member 11 in attractive relation with the poles 16 and 1'? of the holding electromagnet against the bias to the released position. A releasing winding 18 is associated with the flux path 19 between the poles 16 and 17' of the electromagnet so as to magnetize the flux path 19 in the direction indicated by the full line arrow upon cur-' rent flow through the releasing winding 18 in one direction, and to magnetize the flux path 19 in the direction indicated by the dotted line arrow upon the flow of current in the reverse direction. With the releasing winding 18 connected to be energized in accordance with the current flowing in the circuit controlled by the switch elements 12 and 13, as indicated by the full line arrow in the drawing, the magnetic member 11 will be re leased for movement in accordancewith its bias uponmagnetization of the flux path 19 in the direction indicated by the full line arrow. With such magnetization of the flux path 19 by the releasing winding 18, the holding flux normally supplied by the main magnetizing winding 15 is shifted from the magnetic member 11 through the flux path 19 in the manner fully described in Tritle Reissue Patent No. 15,441. Briefly, with the releasing winding 18 unenergized, practically all of the flux set up by the main magnetizing winding 15 in the direction indicated by the full line arrow passes from the pole 16 through the armature 11 into the pole 17. Only a very small amount of the flux passes through the flux path 19 due to the relatively high reluctance of the air gap inthis flux path. However, upon energization of the releasing winding 18 so as to exert a magnetizing force upon the flux path 19in the direction indicated by the full line arrow, this magnetizing force acts cumulatively with that of the main magnetizing winding 15 to increase the flux passing through the flux path 19 until practically all of the flux set up by the winding 15 passes through the flux path 19. In this way practically all of the holding flux of the main magnetizing winding 15 is shifted from its initial path through the pole piece 16, the armature 11, and the pole piece 17 into the'fiux path 19. As a result the magnetic member 11 is released for operation in accordance with its bias to carry the switch element 12 to the circuit opening position. It will be observed that when the magnetic member is released by action of the releasing winding 18 the magnetization produced by the releasing winding 18, as indicated by the full line arrow is cumulative with respect to the magnetization produced by the main magnetizing winding 15 through the part of the magnetic circuit on which the winding 15 is disposed and differential with respect to magnetic member 11. In other words, the releasing winding 18 assists the magnetizing winding 15 upon current flow through the releasing winding in'the direction required to effect release of the magnetic member 11. When the current flow through the releasing winding 18 is in the normal direction the magnetizing ampere turns of the winding are opposed to the magnetizing ampere turns of the main magnetizing winding 15 through the part of the magnetic circuit on which winding 15 is disposed, as will be evident from a comparison of the dotted line arrow associated with the re-- leasing winding 18 and the full line arrow associated with the winding 15. In order to prevent any material reduction in the value of the holding flux of the electromagnet 10 under these conditions, the auxiliary'compensating winding 20 is provided in accordance with the present inventions As shown the winding 20 is connected to be energized in accordance with the current flow in the releasing winding 18.

Moreover, the auxiliary compensating windby the interrupter in the direction indicated by the full line arrow. With current flowing in circuit 21 in the normal direction, as indicated by the dotted arrow, the releasing winding 18 and the auxiliary compensating winding 20 set up a magnetizing force in the direction indicated by the dotted arrows.

It will be observed that an overload circuit interrupter 22 of the usual type having a tripping winding 23 for efiecting operation upon the occurrence of excessive current is connected in the circuit 21 controlled by the reverse current circuit interrupter previously described. With the arrangement as shown the operation of the reverse current circuit interrupter embodying the invention is as follows: With the current flowing in the circuit 21 in the normal direction, indicated by the dotted line arrow, the magnetizing force of the auxiliary compensating winding 20 acts cumulatively with the magnetizing force set up by the holding winding 15 and thereby serves to strengthen the holding flux of the magnet 10. In this waycompensation is obtained for the opposing magnetizing force of the releasing winding 18 which otherwise would tend to reduce the holding flux of the electromagnet 10, as previously pointed out. When the current flow in the direction indicated by the dotted arrow in the circuit 21 increases to an excessive value the overload circuit interrupter 22 responds to interrupt the circuit. This results in deenergizing the releasing winding and also the auxiliary compensating winding 20. How ever, with the holding flux of the electromagnet 10 having been previously maintained by the compensating winding 20 at substantially nor mal value the magnetic member 11 is maintained in the attracted position so as to hold the movable switch member 12 in contact with the cooperatings'witch member 13. Thus, upon reclosure of the overload circuit breaker 22 the circuit is reestablished.

In case the current flow in the circuit 21 should reverse, as indicated by the full line arrow, the magnetizing action of the releasing winding 18 and the auxiliary compensating winding 20 likewise are reversed, as indicated by the full line arrow associated therewith. When'the current flow in the reverse direction reaches a certain value the releasing winding 18 functions quickly to divert or shift the holding flux of the electromagnet 10 from the magnetic member 11 through the magnetic flux path 19. magnetic member 11 to operate the switch mem-.- ber 12 to the circuit opening position in accordance with its bias. The value of current required to eflect operation of the reverse current circuit interrupter may be materially below that required to produce operation of the overload circuit breaker 22. With the reverse current flowing through the winding 20, the magnetizing actionof this winding opposes that of the main magnetizing winding 15 thereby reducing the value of the holding flux of the electroniagnet through the magnetic member 11, in addition to the flux shifting action of the releasing .windi 18. v

permits the 1 provided for both the releasing winding 18 and the auxiliary compensating 20, or for either of them. Also, instead of a special compensating winding 20, as illustrated, a single conductor can be associated with the holding electromagnet so as to have the same eifect.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An electroresponsive device comprising a movable magnetic member, an electromagnet for magnetically holding the same in a predetermined position, a releasing winding associated with the electromagnet to render the holding force thereof inefie'ctive upon a predetermined current flow in a predetermined direction in the releasing winding, and means operable upon current flow in said releasing winding in a direction opposite to said predetermined direction forpreventing material variation in the holding force of said electromagnet.

2. An electroresponsive device comprising a movable magnetic member, an electromagnet having a normally energized magnetizing winding for magnetically holding the said magnetic member in a predetermined position, a releasing winding associated with the electromagnet for diverting the holding flux of the electromagnet to render the holding efiect thereof ineifective upon a predetermined current flow in a predetermined direction in the releasing winding, and means operable upon current flow in the releasing winding in a direction opposite to said predetermined direction for preventing material variation in the holding force of the electromagnet. j

3. An electromagnetic device comprising an electromagnet having a normally energized magnetizing winding, a movable magnetic member under the control of the electromagnet, a separate magnetizing winding for magnetizing a flux path between the poles of said electromagnet to effect operation of the movable magnetic member upon a predetermined current flow in said separate winding in a'predetermined direction, and means associated with the electromagnet for preventing operation of the movable magnetic member upon' the interruption of current flow in said separate magnetizing winding in a direction opposite to said predetermined direction.

4. An electroresponsive device comprising a movable magnetic member, an electromagnet for holding the member in a predetermined position, a winding operatively associated-with the electromagnet for shifting the holding flux from the said magnetic member upon current flow through the winding in a predetermined direction, and an auxiliary winding energized in accordance with the current'flow through said first winding and arranged to increase the magnetization of the electromagnet upon current flow through said releasing winding in the opposite direction.

5. An armature device comprising a movable member, an electromagnet for holding the member in a predetermined position, a releasing winding responsive to the current in the circuit and associated with the electromagnet for rendering the holding flux thereof ineffective upon a predetermined current flow in the circuit in a predetermined direction, and a compensating winding energized in accordance with the current flow in the releasing winding and arranged .to strengthen the holding flux of said electromagnet upon current flow in the circuit in the opposite direction.

6. An electroresponsive device comprising a movable magnetic member, an electromagnet for magnetically holding the same in a predetermined position, a releasing winding associated with the electromagnet to render the holding force thereof ineffective upon a predetermined current flow in a predetermined direction in the releasing winding, and a compensating winding energized in accordance with the current flowing in the releasing winding for'preventing material variation in the holding force of the electromagnet upon current flow in the releasing winding in the opposite direction.

7. An electroresponsive device comprising a movable magnetic member, an electromagnet for magnetically holding the member in a predetermined position, a winding arranged to control a flux path for shunting the holding flux of the electromagnet from said movable magnetic member upon current flow in the winding in one direction and operating to decrease the holding flux of the electromagnet upon current flow in the winding in the other direction, and a second winding connected to be energized in accordance with the flow of current in said first winding and associated with the electromagnet to strengthen the holding flux of the electromagnet upon current flowing through said first winding in said other direction.

8. An electromagnetic device comprising an electromagnet, a movable magnetic member arranged to be held in attractive relation with the poles of the electromagnet, said electromagnet.

having a magnetic structure providing a flux path between the poles thereof independently of said and a second winding connected with said first winding and associated .with the magnetic structure of said electromagnet to increase the holding flux thereof upon current flow through the first winding in the opposite direction.

9. An electroresponsive armature device comprising a movable member, an electromagnet having a normally energized magnetizing winding and a movable magnetic member for controlling the operation of said armature member, said electromagnet having a flux path between the poles thereof independent of the movable magnetic member, a winding for controlling the magnetization of said magnetic flux path to effect operation of the movable magnetic member upon a predetermined current flow in the circuit in a predetermined direction, and an auxiliary winding connected to .be energized in accordance with the current flow in said first winding and associated with the electromagnet to increase the magneti-- rent flow in a direction opposite to a normal direction, and means operable upon current flow in said releasing winding in said normal direction for preventing material variation in the holding force of said electromagnet whereby said member is maintained in said one position against said bias during normal current flow irrespective v of the magnitude of said current. HANS GRUNPlOLZ. 

